SpaceX launched the seventh test flight of its Starship rocket on Thursday, but lost communication with the upper stage of the rocket that continues on into space.The company’s webcast showed data stopped transmitting from Starship about nine minutes into the launch.

Elon Musk’s spaceflight company is continuing its work on the vehicle that could one day take people to the moon and eventually Mars.

At 403 feet tall, Starship is the biggest launch vehicle ever. It’s made up of two parts: the Starship spacecraft, which is designed to carry crew and cargo into orbit, and the Super Heavy Booster, which comes with 33 SpaceX Raptor engines that help propel Starship into space.